This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Autoantibodies have been detected in IVIG preparations. There is a theoretical concern that autoantibodies could cause damage to patients receiving these infusions, or cause false positive tests in patients on IVIG. This is of concern because patients with primary immunodeficiency on replacement IVIG therapy who then develop autoimmune disease may be evaluated with autoantibody levels. This study aims to determine whether replacement IVIG infusions in patients with primary immundeficiency who do not have clinical autoimmune disease have increased autoantibody titers post-IVIG infusion. This data will aid in the interpretation of serologic tests for autoimmune disease in patients on IVIG.